1. Field of the Invention
The present invention relates to a marine drive shaft-bearing structure in which a bearing member is received in a bearing chamber within a bearing body, a drive shaft is rotatably supported by the bearing member, and a grease filling portion is provided to provide grease to the bearing chamber.
2. Description of Background Art
Marine drive shaft-bearing structures are known wherein a bearing body is provided between an engine and an impeller. A drive shaft for the impeller is rotatably supported by the bearing body via bearing members (ball bearings) with sealing members being provided at both ends of the bearing body to define a bearing chamber for sealing the bearing member. A grease filling portion is provided to provide grease to the bearing chamber and a breather portion is provided to absorb the expansion of the grease or air in the bearing chamber. See, e.g., Japanese Patent Laid-open No. 2003-89399.
In addition, the drive shaft for the impeller is adapted to connect the output shaft of the engine to the impeller shaft for a water jet pump. The rotation of the engine is transmitted by this drive shaft to an impeller shaft to rotate an impeller.
The rotation of the impeller drives the water jet pump for providing propulsion to the watercraft.
The grease filling portion of the Japanese Patent Laid-open No. 2003-89399 is configured as set forth below. A grease filling port is formed in the bearing body to communicate with the bearing chamber. A connection tube is attached to the grease filling port and communicates with a grease supply hose. A grease nipple attached to the end of the grease supply hose is attached to the upper portion of a watercraft body.
In addition, because the connection tube is attached to the grease filling port of the bearing body, it is disposed in the vicinity of the bottom portion of the watercraft body. Further, the grease nipple is attached to the upper portion of the watercraft body.
Thus, since the distance between the connection tube and the grease nipple is relatively large, the grease supply hose used to connect the connection tube with the grease nipple is relatively long.
When grease is filled in the bearing chamber of the bearing body using the grease filling portion, a grease gun (grease injector) is used to inject the grease from the grease nipple. The grease thus injected is filled in the bearing chamber through the grease supply hose, the connection tube and the grease filling port.
However, the grease filling portion set forth in Japanese Patent Laid-open No. 2003-89399 requires a grease gun because grease is injected from the grease nipple and the grease is likely to adhere to the vicinity of the grease nipple.
If the grease adheres to the vicinity of the grease nipple, wiping off the adhering grease involves an effort. Therefore, there is a need for practical use of a technique that can simply fill grease into a bearing chamber without use of a grease gun and without any effort.
On the other hand, in the grease filling portion, the grease supply hose having a relatively large length is connected to the connection tube and the grease nipple is attached to the end of the grease supply hose. Therefore, the number of component parts is increased and the cost of the grease supply hose is increased. This makes it difficult to suppress the cost.